Extrusion die-head overview
Every plastic pipe extrusion operation starts off with two basic stages. The first stage is the extruder, which receives the plastic granules and melts them through multiple heating, mixing and compressing zones, outputting a steady and consistent stream of molten plastic. The second stage is the extrusion die-heads, which is the assembly that receives the molten plastic output, which shapes it into the desired pipe profile.
The purchasing of an Extrusion die-head is one to research thoroughly, since it is an investment that will heavily influence both your product quality and your production costs and operation.
What to look for in an extrusion die-head
Overall quality of construction & materials
As with any piece of industrial equipment, an important factor for a quality extrusion die-head is the overall materials and build quality. This pertains to both the quality of the metals used for machining the molten plastic contact parts, as well as to the sensors used to monitor temperature and pressure in various points throughout the extrusion die head.
DRTS plastic extrusion die-heads are made of special types of metal alloys that are able to operate as intended within the specified application conditions. Moreover, DRTS uses high quality sensors from world class manufacturers such as Gefran (Italy) or Gneus (Germany), ensuring reliable operation and ease of servicing.
A very important die head feature for every pipe products manufacturer is to be able to produce multi layered pipe, gaining multiple advantages, such as:
- Cost savings, by producing pipe in which only a small portion of the pipe is made of virgin raw material (20% in 3 layer or as low as 10% in two layer configurations), while the material for the remaining 80% or 90% layer is made using lower cost regrind or off-spec materials.
- Product coloring and visual identification, by having the capability to coat the thin outer section of pipe with a specific colored outer layer, or even incorporate colored marking lines on the pipe.
DRTS offers the 3-layer cross head, capable of producing single, double or 3 layer pipe, as well as operate in ABA or ABC configuration (with or without stripes respectively).
DRTS offers several extrusion die-head features that allow for flexible die head operation, such as easy and fast pipe format changeover, easy die head operation & integration, and the ability to fit the die-head to any existing or new plastic pipe extrusion line.
Optimized die design
An optimized die design results in high product quality and increased service life. DRTS uses spiral die configurations, which produce uniform pipe, free of weld lines or internal stresses, resulting in high quality, pipe products. Moreover, all of the die-head’s molten plastic contact surfaces are designed and machined with the appropriate angles, low roughness and flush geometry, to avoid unwanted decompression areas and consequently require less maintenance. Also optimized, is the length of the die’s exit region, known as land area. Too short land length results in unstable flow and pipe dimensional stability, while a too long land length will introduce unnecessary friction, adding to the back pressure of the die head. Our extrusion die-heads are designed to eliminate high back pressure which can result in lower die head outputs and efficiency
The extrusion extrusion die-head is a key part in every pipe extrusion production operation and as such, it is one of the parts that define the quality and operational stability of your manufacturing process. Download your copy of the DRTS 2018 Pipe Extrusion Technology Report to find out more about all the parts that make up pipe production lines, the current state and latest trends in pipe extrusion technology.